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Author Topic: Anybody clued up on DNS 'A' and 'CNAME' records?  (Read 11804 times)

sevenlayermuddle

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Anybody clued up on DNS 'A' and 'CNAME' records?
« on: January 20, 2013, 11:16:39 AM »

Fairly specialist stuff here, not many folks may be interested.  But I spent most of a day on it (including a DNS learning curve), so on the offchance anybody finds it useful...

As part of my recent encounter with google apps, I had to go through their site verification process, which can be done by adding a random-looking record to the DNS, either as a TXT or a CNAME.   You can also verify by putting a token on your website or in the html, but that seems messy as I want to keep email and website completely separate.

My domain is managed by freeparking.co.uk, who (Yuk!) only allow a single TXT record that I may want to use for other purposes, so I tried using CNAME.  The CNAME associates a random looking alias of my domain, with a random looking google domain name, which convinces google that I own the domain.

But again, freeparking have messed up CNAME config.  You can create a CNAME record, but only as an alias to one of your own subdomains.  I think this restriction is all wrong and utter madness, but searches confirm it to be the case with freeparking, and they are showing no signs of commenting upon it or fixing it.

However, whereas an 'A' record should contain a numerical IP address, freeparking allow you to add an 'A' record that contains a fully qualified domain name where the IP address might go.  My understanding (which may be wrong?) is that such a DNS entry would be invalid, but I tried it to see what happened, it seemed to be accepted.  I then checked the DNS with Linux 'dig', and found that DNS reported my new (and theoretically invalid) 'A' record showed up as a valid 'CNAME'.    :o

;; ANSWER SECTION:
random-string.some-domain-of-7lm.com. 86400 IN CNAME different-random-string.domainverify.googlehosted.com.


Then I went back to google, and clicked 'verify' which was instantly accepted. :graduate:

Above may be of interest to anybody else who ever tries to get google apps to work with a domain managed by freeparking.  But I'd also be interested in any comments on the problems I encountered, or the solution I found.   Anybody seen anything like it before?  Is my new CNAME record (created as an 'A' record) in safe territory, or how likely that it may all stop working tomorrow?
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kitz

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Re: Anybody clued up on DNS 'A' and 'CNAME' records?
« Reply #1 on: January 20, 2013, 09:10:53 PM »

Im honestly not sure, but I thought CNAME was for aliases?

Most of my domain names and hosting are all with the same company so I dont really have this issue, but iirc I used to point the whole DNS to where-ever I was hosting by just inserting the DNS and pointing to the relevant NameServers.

Because you are splitting the hosting and email I should imagine it gets a lot more complicated and I wouldnt know which goes where :/
Id probably just raise a ticket and get my hosts to do it  :D  Unfortunately though that isnt much help for you :(
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sevenlayermuddle

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Re: Anybody clued up on DNS 'A' and 'CNAME' records?
« Reply #2 on: January 20, 2013, 09:35:34 PM »


Id probably just raise a ticket and get my hosts to do it  :D  Unfortunately though that isnt much help for you :(

Actually it is, it further underlines the benefit of finding a competent host who offers good support, which is something I'll be considering in coming weeks in relation to my other recent thread.   :)
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guest

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Re: Anybody clued up on DNS 'A' and 'CNAME' records?
« Reply #3 on: April 19, 2013, 10:08:53 PM »

Google apps use DNS extensions so if you try to use a cname which points at one of the google app servers then it can end in tears quite frequently - usually due to the "idiot-proof" control panels your webhost uses most times.

I went through something like this with a guy using it for blogging but he was having problems with some users running a DNS server on Windows being unable to resolve the cname.

Far from it being Windows at fault it was in fact down to Windows being the only RFC-compliant DNS server and there was in fact an error in the zonefile for the cname (which was Google). On its own that would have been mainly fine but the "idiot-proof" control panel the webhost had was pointing a cname at an out of zone cname which Windows correctly identified as being an unresolvable lookup due to the error which was trivial to fix had they access to the zonefile, which of course they don't (just the control panel).

So in short - yes it will probably work for most people who don't have a Windows server as a DNS resolver. For those that do its quite likely your cname site won't resolve at all if it involves Google, a cname and cpanel. YMMV of course.

The long answer is much longer and I will lose the will to live (again) should I have to work through it with you :P Change host is probably the best answer.
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sevenlayermuddle

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Re: Anybody clued up on DNS 'A' and 'CNAME' records?
« Reply #4 on: April 19, 2013, 10:51:06 PM »

Thanks for the info Rizla, but my question wasn't really aimed at google, or at Windows.

Rather my question was, does the seemingly invalid 'A' record, that freeparking allowed me to create ( with qualified domain name rather than numeric IP) , really amount to a valid CNAME record, which is what I wanted?   It certainly looked a lot like a CNAME from DNS look ups.

At the end of the day google accepted my authentication and all is working well.   And that may be useful to any other freeparking customers who want to use google apps.  But nevertheless... I remain curious... did Freeparking actually create a CNAME or an (invalid) 'A' record?
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d2d4j

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Re: Anybody clued up on DNS 'A' and 'CNAME' records?
« Reply #5 on: October 16, 2014, 10:37:12 PM »

Hi

I would think free parking created an actual A record, not a cname but because the NS are with same provider, within the hosting platform, it will be a virtual domain, hence why it will show. Conversely, it could be a cname pointing to the main host on the hosting platform, or perhaps listed as a pointer domain.

To answer the question over dns records, it is feasible and very often the case, where the hosting records (A and or Cname) are on different platforms to the email (MX)

You have to remember the dns records just simply resolve names to ip addresses, for ipv4 and ipv6 networks.

I hope that helps a little

Many thanks

John
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sevenlayermuddle

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Re: Anybody clued up on DNS 'A' and 'CNAME' records?
« Reply #6 on: October 20, 2014, 12:07:52 AM »

Thanks.   For the record, since starting this thread I have begun to migrate my domains to Vidahost, following recommendations in another thread from a while ago.

Their DNS control panel is a lot more logical, allowing one to simply add new records, selecting type (Cname, A, Txt etc) from pulldown list.  My impression is, if you enter data that is invalid for the selected record type, the whole record just gets discarded.    But as long as I enter valid data, should I ever want to open transfer another domain to google apps, it should be plain sailing.  :)

However, google apps validation is a once-only event so, having already validated, I didn't have to do it again with Vidahost and I should never have to do so again.   Unless of  course I ever want to host a new domain with google which is unlikely as google apps is no longer free.    :(

PS, impressed by Vidahost so far.  Great to have UK phone support, and contrasts with Freeparking's contact info that basically says they will hang up on you if you call them by phone, unless you are a policeman.
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kitz

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Re: Anybody clued up on DNS 'A' and 'CNAME' records?
« Reply #7 on: October 20, 2014, 10:20:37 AM »

Glad everything has gone ok so far.   The support is one of the reasons why I personally rate Vidahost.   I mostly use tickets rather than phone, just so I can put what I want in writing.   Admittedly Ive not raised a ticket for months as I envisage being on this particular package for a while and now everything is set up there isnt much need to do anything else..  but Ive always found the response time second to none and usually a reply within minutes.
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